# Questions tagged [schubert-cells]

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12
questions

**3**

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71 views

### Flat $\mathbb{Z}$-lifts of Schubert cells and isomorphism for local cohomology groups

Let $G$ be a connected quasi-split reductive group over a field $k$ of characteristic zero with Weyl group $W$ and a Borel $B$.
Set $X:=G/B$, $C(w):=BwB/B \subset X$ for $w \in W$ the Schubert cell ...

**3**

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137 views

### Trivial morphism between local cohomology groups

I have two questions concerning morphism between local cohomology groups which I think are related.
Let $G$ be a reductive group with Weyl group $W$ and $B \subset G$ a Borel. Let $X=G/B$ be the flag ...

**8**

votes

**1**answer

230 views

### Union of Schubert cells being affine

Let $k$ be a field of characteristic zero, $G$ be a reductive group with a Borel $B$ and $\mathcal{F}:=G/B$ the associated flag variety. Let $W$ be the Weyl-group of G.
Then let $S \subset W$ and $Z=\...

**1**

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58 views

### Generically intersecting Schubert cycles

I have a question about the the proof of Pieri's formula from Harris' and Eisenbuds's lecture "3264 and All That"on page 146. Before the proof we use this terminology (see page 139):
let $G=G(k,V)$...

**3**

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70 views

### Flag variety over quaternions and its Hecke algebra

Consider cell decomposition of flag variety of $\mathbb{H}^{n}$ into orbits under the action of $B(\mathbb{H})$ - group of upper triangular matrices with coefficients in $\mathbb{H}$. I think cells ...

**2**

votes

**1**answer

160 views

### Typo in a paper definition of Schubert cells?

In the paper "Quantum state transformations and the Schubert calculus" by Sumit Daftuar and Patrick Hayden (Annals of Physics 315 (2005) 80-122) on page 91, we have following notations:
$A_r$ denotes ...

**2**

votes

**1**answer

127 views

### Can Schubert cells be defined, set theoretically, by less equations then the standard ones?

Let $V = \mathbb{C}^n$ with basis $e_1,\dots,e_n$, and $U = \langle e_1,\dots,e_k\rangle$. Let
$$\Sigma(U)=\{\sigma\in Gr(V,2)\mid \sigma\in U \}$$
be the Schubert cell of $2$-planes contained in $U$....

**2**

votes

**1**answer

436 views

### Schubert calculus and Pieri's formula

In the lecture notes Grassmannians: the first example of a moduli space. MIT Open Course Ware. page 7:
Are there any formal publications (books/papers) where I can find the formula?

**3**

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71 views

### Can Bruhat cells in semi simple groups be induced from matrices?

Let $G$ be a semisimple Lie group. Embed it as a subgroup into a special linear group of suitable rank, $SL(n)$ (real or complex). The question is: is it always possible to find such an embedding, ...

**1**

vote

**1**answer

261 views

### Schubert problems to cycle class in Grassmanian

Say I have a family of linear spaces, and that I can solve all Schuber problems of that family (that is, how many members of the family pass through a set $S$ of linear spaces,
where we consider all ...

**16**

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510 views

### Comparing the Kazhdan-Lusztig and Steinberg pre-orders

Both Kazhdan-Lusztig and Steinberg have defined pairs of preorders on $S_n$. Kazhdan and Lusztig's preorders come from their basis:
We write $x\leq_L y$ if any left ideal spanned by K-L basis ...

**14**

votes

**1**answer

2k views

### Detailed proof of cup product equivalent to intersection

Consider a smooth, closed, compact finite-dim manifold. We have Poincare Duality to relate the cocycles and cycles.
I would like to know where I can find
a reference for a proof that the cup
...